For await of

How to make multiple HTTP requests efficiently in JavaScript?

Have you ever faced the need to make multiple HTTP requests in a web development project? This is a common challenge, especially when interacting with multiple APIs at the same time. The most efficient solution is to use the for await...of loop, combining async and await to execute promises asynchronously. This not only makes the code cleaner, but also improves performance and user experience by not blocking the loading of other elements in the application.

What is for await...of and how does it work?

The for await...of is a powerful tool in JavaScript. It is a loop that allows us to iterate over asynchronous objects, such as promises, so that we can wait for each one to resolve before proceeding to the next one. The syntax is intuitive and adapts well when you need to work with multiple HTTP requests.

For example, let's say you have an array of URLs from an API, such as Rick and Morty. You can iterate over each URL and perform an asynchronous fetch request as follows:

async function fetchNewData() { const URLs = [ 'url1', // Replace with real URLs 'url2', 'url3' ];
 try { for await (let URL of URLs) { let response = await fetch(URL); let data = await response.json(); console.log(data); } } } catch (error) { console.error('Error:', error); } }}
 fetchNewData();

How to structure the code to handle errors?

Error handling is critical when working with asynchronous requests. Using try...catch blocks is the recommended way to catch and handle errors, such as network request failures. This ensures that your application does not fail completely if one of the requests fails and you can react appropriately, for example, by displaying an error message to the user.

Within the for await loop, the try block is responsible for performing the fetch and converting the response to JSON format. If any of these operations fail, control is passed to the catch block, where we can handle the error in an elegant way.

What are the benefits of using for await...of in real projects?

• Non-blocking performance: Executing requests asynchronously allows the browser to continue processing other UI elements, improving the experience.
• Cleaner and more manageable code: By using async/await, your code becomes more readable and easier to maintain compared to traditional promises or callbacks.
• Scalability: You can easily adapt this approach to handle more URLs or add additional logic to process each response.

Implementing these techniques in your projects not only optimizes their performance, but also provides a robust foundation for handling complex scenarios where multiple data elements must be loaded and processed simultaneously. So, go ahead and apply for await...of in your future developments and experience the improved efficiency and fluidity of your applications!